Reactions of fatty materials with oxygen. XVIII. Catalytic hydrogenation of autoxidized methyl oleate and oleic acid. Preparation of monohydroxystearic acids

Summary Autoxidation of methyl oleate and oleic acid beyond the peak peroxide values followed by catalytic hydrogenation gave mixed monohydroxystearic acids in high yield. The complicated autoxidation mixture which contains peroxides, hydroxy, carbonyl, and oxirane compounds was simplified considerably in composition by this procedure. For complete reduction of the double bond, and the carbonyl and oxirane groups, hydrogenation was conducted at about 150° and 150 lbs.. Peroxides were reduced at room temperature. Catalysts used were palladium on carbon and Raney nickel. The selective reduction of peroxides in autoxidation mixtures has been studied by chemical and catalytic means. Peroxides were converted largely to carbonyl compounds rather than to the anticipated hydroxy compounds. Palladium-lead on calcium carbonate is an excellent catalyst for reducing peroxides with hydrogen. tert-Butyl hydroperoxide, 12- ketostearic acid, stearone,cis-9,10-epoxystearic acid and methyl oleate peroxide concentrate were employed as model substances in determining hydrogenation conditions. Paper XVII. is reference 5. Presented at the fall meeting of the American Oil Chemists' Society, Minneapolis, Minn., Oct. 11–13, 1954. A laboratory of the Eastern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

Reactions of fatty materials with oxygen. XVII. Some observations on the secondary products of autoxidation of methyl oleate

Summary Methyl oleate, autoxidized for short and long periods of time, has been fractionated with urea. Up to a peroxide content of about 15% the autoxidation mixture can be cleanly separated into a peroxide concentrate containing 90% peroxide and unoxidized methyl oleate. From about 15% peroxide to the maximum peroxide content (35–40%) concentration to only about 70% peroxide can be obtained, and the remaining material is largely a mixture of oxygenated compounds and residual methyl oleate. If the autoxidation is conducted beyond the peak value in peroxide content, little, if any, concentration of peroxide can be obtained. Also, beyond the peak in peroxide value and in the range of 30–20% peroxide, methyl oleate is substantially absent and the autoxidation mixture consists almost entirely of oxygenated compounds containing only one functional group in the chain. Evidence is presented which shows that in the autoxidation of methyl oleate substantially all of it undergoes single attack by oxygen (or peroxides) before any significant quantity of multiple attack occurs. α,β-Unsaturated carbonyl compounds are among the important secondary products of autoxidation. Paper XVI is reference 14. Presented at the Fall Meeting of the American Oil Chemists' Society, Minneapolis, Minn., Oct. 11–13, 1954. A labortory of the Eastern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

Reactions of fatty materials with oxygen. XX. Recent developments in the autoxidation of methyl oleate and other monounsaturated fatty materials

Summary Some significant developments since 1947 in the autoxidation of methyl oleate and other monounsaturated fatty materials have been reviewed and critically evaluated. Subjects discussed are preparation and characterization of hydroperoxides, and mechanism, kinetics, and secondary products of autoxidation. Major developments in the field have resulted largely from the use of newer instruments (polarograph, infrared spectrophotometer) and separation techniques (urea complexes, molecular distillation, countercurrent distribution). Direct experimental evidence is now available which demonstrates that a) hydroperoxides are the predominating, but not the exclusive, primary products of autoxidation; b) the hydroperoxides obtained from methyl oleate are mostly, if not entirely,trans; c) substantially all the methyl oleate undergoes single attack in the chain before any significant amount of multiple attack occurs, and d) α,β-unsaturated carbonyl compounds are among the most important secondary products of autoxidation. Paper XIX is reference 66a. Presented at the Fall Meeting of the American Oil Chemists' Society, Philadelphia, Pa., October 10–12, 1955. A laboratory of the Eastern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

The oxidation of methyl oleate. II. A reaction between methyl hydroperoxido oleate and oleic acid

Oleic acid is intermolecularly oxidized by methyl hydroperoxido leate at 90°C, through the addition of oxygen at the olefinic bond with the formation of opexy and dihydroxy compounds. Only the lowmelting isomeric form of dihydroxystearic acid could be isolated from the reaction mixture. The oxidation of olefinic linkages by hydroperoxides appears to account, at least in part, for the observed reduction of unsaturation in autoxidizing fats. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Influence of high energy radiation on the oxidation of oleic acid and methyl oleate. II. Sites of oxygen attack

1. The hydroperoxides formed by the γ-irradiated autoxidations of methyl oleate at 7.5°C. and 56°C. have been characterized. The mono- and dicarboxylic acids produced by γ-irradiated autoxidation at 56°C. and by cobalt-catalyzed γ-irradiated autoxidation at 73°C. have also been examined.
2. The hydroperoxides were found to be a mixture of the 8-, 9-, 10-, and 11-hydroperoxidoöleates in both samples. They were present in the order 10>11> 9>8.
3. Evidence is presented for the presence of octanoic, nonanoic, octandioic, and nonandioic acids in the 56°C. autoxidation. Octanoic and nonanoic acids were also present in the cobalt-catalyzed autoxidation.
4. No significant departure from non-irradiated autoxidations was found.

     

Reactions of fatty materials with oxygen. XVI. Relation of hydroperoxide and chemical peroxide content to total oxygen absorbed in autoxidation of methyl oleate

Summary Methyl oleate has been autoxidized at 100°, 80°, and 60° in the Barcroft-Warburg apparatus. Samples have been analyzed for total peroxide by the iodometric method and for hydroperoxide by the polarographic method. These peroxide values have been compared with each other and with total oxygen absorbed. The relation of chemical peroxide (y_c) to oxygen uptake (x) is expressed by y_c=1.09x^0.936. This equation is equally valid at the three temperatures for the first 150 millimoles (15%) of oxygen absorbed per mole of methyl oleate. Similarly, the hydroperoxide content (y_h) for the first 150 millimoles of oxygen absorbed at 80° and 100° is given by the equation y_h=1.02x^0.936. The ratio of hydroperoxide to chemically determined peroxide was, on the whole, constant throughout the entire range of oxidation (15–300 millimoles of oxygen absorbed per mole), and averaged about 95%. It has been shown unequivocally that the major portion of the peroxides formed in the autoxidation of methyl oleate are hydroperoxides, confirming conclusions of recent investigators. A small but significant amount of non-hydroperoxidic peroxide appears to be formed concurrently. Paper XV is reference 6. Presented at the Spring meeting of the American Oil Chemists' Society, San Antonio, Tex., April 11–14, 1954. A laboratory of the Eastern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

Influence of high energy radiation on oxidation of oleic acid and methyl oleate

Summary 1. Gamma radiation from Cobalt 60 influences the oxidation of oleic acid and methyl oleate even at low temperatures. 2. Determination of peroxide values, carbonyl values, and the E _1cm ^1% . values at 224 mμ revealed that high peroxide values could be obtained but that secondary products are formed in appreciable quantities. 3. The products causing absorption at 224 mμ may be α,β-unsaturated ketones. The level of these substances can be increased by irradiation-oxidation in the presence of metal soaps such as cobalt stearate. 4. Irradiation-oxidation of methyl oleate through a series of temperature ranges from 7.5°C. to 55°C. reveals a marked thermal activation effect. Peroxide values of 2000 me/kg or greater are obtained in 100 hrs. of reaction time. Journal Paper No. 125, American Meat Institute Foundation. Supported by a grant from the National Renderers Association and from Darling and Company. Presented at the fall meeting, American Oil Chemists’ Society, Philadelphia, Pa., Oct. 10–12, 1955.     

Compatibility of derivatives of 9,10-dihydroxystearic acid and 9,10-dihydroxyoctadecanol with some commercial polymers

Summary A study of compatibility with some commercial polymers is reported for some alkyl and alkenyl esters of low-melting 9,10-dihydroxystearic acid, 9,10 (10,9)-alkoxyhydroxyoctadecanols, esters of 9,10(10,9)-alkoxyhydroxystearic acids, and two series of previously unreported compounds, namely, esters of the isomeric 9,10-dihydroxystearic acids with ether-alcohols and polymeric plasticizers prepared by the reaction of selected members of this group of new esters with phthalic anhydride. The most promising materials are methyl 9,10-(10,9)-methoxyhydroxystearate, esters of 9,10-dihydroxystearic acid with ethylene glycol monobutyl ether and ethylene glycol monobenzyl ether, and the polymeric plasticizers. The last-named group is compatible with polymers which differ widely in chemical structure. Presented at the meeting of the American Oil Chemists' Society, Atlanta, Ga., May 1950. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Isomerization studies: II. Thermal alteration of oleic acid and methyl oleate in the presence of mineral catalysts

A structure analysis has been conducted on the distillable fraction (67–71%) obtained from the clay catalyzed isomerization of methyl oleate and oleic acid. The method of analysis involved the combined use of reductive ozonolysis, urea adduction, and gas liquid chromatography-mass spectrometry. The results of this study indicate that the original unsaturation of the fatty acid is mostly retained, but less than the theoretical amount of hydrogen is absorbed when the products are subjected to low pressure catalytic hydrogenation. These results in conjunction with the gas liquid chromatography-mass spectrometry data suggest that branching of the carbon chain has occurred.     

氧气催化氧化苯氧乙醇合成苯氧乙酸

以苯氧乙醇和氧气为原料,经催化氧化合成苯氧乙酸。用高效液相色谱仪（HPLC）进行定量分析,红外吸收光谱（FT-IR）、核磁共振(HNMR、CNMR)、气质联用（GC-MS）对产品进行了定性分析。考察了催化剂、溶剂对反应的影响,并对反应的单因素进行了考察。结果表明：N-羟基邻苯二甲酰亚胺(NHPI）为主催化剂,丁二酮肟和乙酸钴为助催化剂,乙腈是为溶剂;固定苯氧乙醇为0.1mol, NHPI用量为苯氧乙醇摩尔量的8%,催化剂配比是n(NHPI)∶n(丁二酮肟)∶n(乙酸钴)=8∶7.5∶1,0.8 MPa氧压力,80 ℃反应6 h,在此条件下,苯氧乙酸收率达68.6%。并根据GC-MS分析结果提出了可能的反应途径。     

The oxidation of methyl oleate I. The preparation,properties and reactions of methyl hydroperoxido oleate

Summary Low temperature fractional crystallization from acetone has been applied to the separation of methyl hydroperoxido oleate in 85 to 90 percent purity from partially oxidized methyl oleate. The hydroperoxido ester was subjected to hydrogenation, oxidative fission, and reduction with hydrogen iodide. Certain characteristics of the original hydroperoxide and its reaction products have been described. The results obtained lend definite support to the view that the first oxidation product of methyl oleate is a mixture of 8- and 11-hydroperoxido octadecenoic acids, at least under the conditions employed,i.e., oxidation under the influence of ultraviolet light or reaction temperatures up to 60° C. The spectral absorption of methyl hydroperoxido oleate and some derived products was determined. The hydroperoxide group was shown to have no characteristic absorption in the ultraviolet region. The reactions of the peroxide with alkali, hydroxylamine, lead tetraacetate, and α-tocopherol have been described and discussed. Presented before the 37th Annual Meeting of the American Oil Chemists' Society, New Orieans, Luisiana, May 15–17, 1946. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

The peroxidic species generated by ozonolysis of oleic acid or methyl oleate in a carboxylic acid medium

The ozonolysis of oleic acid or methyl oleate in a carboxylic acid medium produces three major peroxidic species as well as aldehyde. These peroxidic compounds have been identified as 1-acyloxyalkyl-1-hydroperoxides, 1,2,4-trioxolanes, and bis(1-acyloxy-1-alkyl) peroxides. The bis(1-acyloxy-1-alkyl) peroxides have not been reported previously as oleic acid or methyl oleate ozonolysis products. A¹H nuclear magnetic resonance examination of the ozonization products of oleic acid or methyl oleate in carboxylic acids, as well as methanol and iso-octane, led to the identification of the peroxidic compounds and aldehyde.     

Liquid-phase oxidation of anthracene in acetic acid with an oxygen/Nitric acid system

Oxidation of anthracene in acetic acid by the oxygen/nitric acid system has been studied and an attempt has been made to ascertain a practical limit of the amount of solvent keeping the commercial prospects in view. The effects of other reaction parameters such as flow rate, amount of nitric acid and water, residence time, etc., have been investigated. While opting for a solvent/substrate ratio of 10, the optimum conversion of anthracene to anthraquinone free from nitro-compounds has been found to be 91% with purity of 98.7%, acceptable to dye-stuff industries.     

Purification of oleic acid,methyl oleate,and oleyl alcohol for use as chemical intermediates

Summary 1. Oleic acid, methyl oleate, and oleyl alcohol of high purity (93 to 96%) were prepared from readily available and inexpensive commercial materials in 65 to 70% yields by fractional distillation and a single low-temperature fractional crystallization. 2. In the fractional distillation of red oil and its methyl esters, lower fractions amounting to about 20% of the starting material were obtained. These are suggested for use in soap manufacture. 3. A fraction containing more than 50% linoleic acid was obtained from the C-18 fraction of red oil by fractional crystallization. This fraction amounted to about 20% of the total starting material and had approximately the same percentage composition of fatty acids as several important semi-drying oils. This paper was presented at the meeting of the American Oil Chemists Society, held in Chicago, on October 7, 1943.     

Structures of ozonolysis products of methyl oleate obtained in a carboxylic acid medium

High-performance liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance spectrometry (NMR) were applied to the analysis of organic peroxide mixtures, which were labile and tended to decompose during analysis. The ozonolysis reaction of methyl oleate gives a peroxide mixture, and, finally, mono- and dibasic acids are obtained by subsequent oxidation. In this study, methyl oleate was ozonized in a nonanoic acid medium, one of the final reaction products. The reaction products were directly analyzed by LC-MS equipped with a frit-fast atom bombardment interface. The molecular ion peak of each peroxide was clearly observed, and its molecular weight was readily determined. On the other hand, each peroxide was fractionated by high-performance liquid chromatography and submitted to structural analysis by NMR. Both results indicated that the reaction products include four peroxidic species: 1,2,4-trioxolaneI, peroxide oligomerII, 1-acyloxyalkyl-1-hydroperoxideIII, and 1-acyloxyalkyl-1′-hydroxyalkyl peroxideIV, as well as an aldehydeV. Ozonolysis of methyl oleate in the absence of solvent produces mainlyI, while that in the presence of a carboxylic acid solvent characteristically produces mainlyIII andIV derived from the solvent.Bis(1-acyloxyalkyl-1-alkyl) peroxide, which was reported previously as a ozonolysis product of methyl oleate, was concluded to beIV in this study. This work was presented at the 31th Annual Meeting of the Japan Oil Chemists’ Society, 1992, Tokyo, Japan.     

Epoxidation of methyl oleate with molecular oxygen in the presence of aldehydes

The epoxidation of methyl oleate with molecular oxygen in the presence of aldehydes was investigated and optimized. Epoxide yields up to 99% were observed in organic solvents. The preponderant radical reaction was started by a single organic radical chain initiator, without using a metal catalyst. The radical character of the reaction was revealed by the concurrent occurrence of trans and cis epoxides and by the prevention of epoxide formation through a radical scavenger. Both branched aldehydes and the linear aldehyde n‐hexanal were well suited in organic solvents. The linear n‐hexanal enabled also a superior epoxide yield of 78% in the green solvent water. The oxidation of high‐oleic sunflower oil under the same conditions with n‐hexanal yielded 39% epoxide groups.     

Solubilities of methyl oleate,oleic acid,oleyl glycerols,and oleyl glycerol mixtures in supercritical carbon dioxide

Solubility isotherms for oleic acid and methyl oleate as well as mono-, di-, and trioleylglycerol (MO, DO, and TO) in supercritical fluid CO₂ at 50 and 60°C are reported. Partition coefficients for quaternary (MO-DO-TO-CO₂) mixtures were obtained at 60°C at pressures ranging from 172 to 309 bar. Data indicate that diolein, and especially monoolein, exhibit positive deviation from ideal behavior, possibly due to intermolecular hydrogen bonding. Supercritical fluid CO₂ appears to be a good media for removal of mono- and diacylglycerol by-products from synthetic triglyceride reaction mixtures at moderate temperatures.     

Autoxidation of fatty materials in emulsion. III. Application of GLC and TLC to studies of the histidine-catalyzed autoxidation of methyl oleate

Methyl oleate, emulsified with sodium dodecyl-sulfate, was extensively oxidized, and the amount of oleate which was reacted was determined by GLC using methyl palmitate as an internal standard. The effects of histidine, iron, and histidine plus iron were compare with the uncatalyzed reaction in the presence and absence of ultraviolet light. Results in the absence of ultraviolet light confirmed previous findings that histidine and histidine plus iron are prooxidants at the concentration studied. In the presence of ultraviolet light the rate of oleate oxidation was about 100× faster than that of the nonirradiated reaction, and the effect of the catalysts was almost negligible. The principal products, determined by GLC and TLC, were epoxide and α,β-unsaturated carbonyl. Hydroperoxy, hydroxy, acid and aldehyde compounds were also present. Epoxy stearate, determined by GLC, compared favorably with epoxy stearate as determined by use of the Durbetaki method. Presented at the AOCS Meeting, Chicago, October 1964. E. Utiliz. Res. Dev. Div., ARS, USDA.     

A study of the volatile compounds produced by the autoxidation of methyl oleate,oleic acid,and cis-9-octadecene

Summary Methyl oleate, oleic acid, and cis-9-octadecene were oxidized at 80° with a stream of air, and the volatile decomposition products were collected in dry ice traps. The volatile material consisted of an aqueous fraction and water-soluble substances, an oil fraction, and a crystalline product. The substances in the aqueous fractions were characterized as formic and acetic acid, and their formation was studied during the autoxidation of the various substrates up to 21 days. The crystalline material was purified, and its properties were examined. The purified crystals showed chemical and infrared properties very similar to a sample of synthesized bis-(hydroxyheptyl) peroxide. Formic and acetic acid were also shown to be produced during the decomposition of hydroxyalkyl peroxides.     

Reactions of unsaturated fatty alcohols. XV. Styrentation of fatty vinyl ether polymers in terpene solvents

Styrenation of fatty vinyl ether polymers in dipentene at 145–165C gives products containing from 20 to 67% styrene by weight but little or no unreacted monomeric styrene remained. After 27 mounths no gelation occurred in these products. Apparently dipentene serves as an effective chain transfer agent during styrenation, keeps the growing polymer chains short, and reduces crosslinking reactions. The amount and type of unsaturation needed in the fatty side chains of the polymer to produce homogeneous products were studied. Ultraviolet and infrared analyses were useful in determining the function of unsaturation in these reactions. Tests on baked films from these products showed that as the amount of styrene was increased, both hardness and alkali resistance were significantly increased. Films prepared from products containing 34 and 67% styrene had Sward hardness values of 10 and 60, and alkali resistance of 33 days and over 65 days, respectively. Films from products prepared in aromatic solventsversus dipentene at the same styrene level showed no difference in hardness, but the alkali resistance of the “dipentene film” was greater. Presented at the AOCS meeting in St. Louis, Mo., 1961. A laboratory of the No. Utiliz. Res. & Dev. Div. ARS, USDA.